The present invention relates to percussive drill assemblies, and particularly to components used to direct high-pressure fluid within drill assemblies including a fluid-operated piston.
One type of commercial percussive drill, commonly referred to as a xe2x80x9cdown-holexe2x80x9d drill due to its intended application, is typically operated by high pressure fluid (e.g., compressed air) that is appropriately directed in order to reciprocate a piston to repetitively impact against a drill bit, the bit having a cutting surface used to cut or bore through materials such as earth and stone. These fluid-operated drills generally have a drive chamber into which the high pressure fluid is directed in order to drive the piston from an initial position to impact the bit. Further, a valve is typically provided to control the flow of percussive fluid into the chamber.
In a first aspect, the present invention is a fluid channeling device for a percussive drill. The drill includes a casing having an interior space, a drive chamber and a valve chamber each being defined within the casing interior space, a piston movably disposed within the casing and having an upper end disposeable within the drive chamber and a longitudinal through-bore, and a valve configured to control flow into the drive chamber and having a surface bounding a section of the valve chamber. The channeling device comprises a first member disposed at least partially within the drive chamber so as to extend into the piston bore when the piston upper end is located within the drive chamber. The first member has an outer surface, an interior space and at least one port extending between the outer surface and the interior space and fluidly connectable with the drive chamber. A second member is disposed at least partially within the first member interior space and has a passage. The passage is fluidly connected with the valve chamber and fluidly connectable with the port so as to establish fluid communication between the drive chamber and the valve chamber.
In another aspect, the present invention is again a fluid channeling device for a percussive drill. The drill includes a casing having an interior space, a drive chamber and a valve chamber each being defined within the casing interior space, a piston movably disposed within the casing and having an upper end disposeable within the drive chamber and a longitudinal through-bore, and a valve configured to control flow into the drive chamber and having a surface bounding a section of the valve chamber. The channeling device comprises a generally tubular body disposed at least partially within the drive chamber so as to extend into the piston bore when the piston upper end is located within the drive chamber. The tubular body has outer and inner circumferential surfaces and a plurality of ports, each port extending between two surfaces and fluidly connectable with the drive chamber. A generally cylindrical body is disposed at least partially within the tubular body and has a passage fluidly connected with the valve chamber. At least one of the tubular body and the cylindrical body is angularly displaceable with respect to the other one of the tubular body and the cylindrical body. As such, each one of the ports is fluidly connectable with the passage at a separate angular position of the tubular body with respect to the cylindrical body so as to establish fluid communication between the drive chamber and the valve chamber.
In a further aspect, the present invention is a drill comprising a casing having an interior space, a drive chamber and a valve chamber each being defined within the casing interior space. A piston is movably disposed within the casing and has an upper end disposeable within the drive chamber and a longitudinal through-bore. A valve is configured to control flow into the drive chamber and having a surface bounding a section of the valve chamber. Further, a first member is disposed at least partially within the drive chamber so as to extend into the piston bore when the piston upper end is located within the drive chamber. The first member has an outer surface, an interior space and at least one port extending between the outer surface and the interior space and fluidly connectable with the drive chamber. Furthermore, a second member is disposed at least partially within the first member interior space and has a passage fluidly connected with the valve chamber and fluidly connectable with the port so as to establish fluid communication between the drive chamber and the valve chamber.